Cooking with cast iron – let’s bust the myths

I love my cast iron pans, they put the most amazing caramalised crust on a steak, give you the best fried onions and you can cook on the cooker top and put them straight into the oven to bake. So versatile, what’s not to love? However, some folks do seem to be scared of cast iron, or think it takes too much looking after. Let’s bust some of the myths.

Myth 1: “Cast iron is hard to look after.”

The myth: Cast iron will rust, chip, or crack easily because it’s a temperamental metal. You need to spend lots of time looking after it, be careful not to knock it against the cooker or other pans in the drawer and be careful when you store it so that seasoning doesn’t chip off!

The truth: Cast iron is tough as nails! (obviously, as they are iron too). Hence why people are still cooking on grandma’s 80-year-old cast iron pans or buying old pans from car boot sales.  The stuff is built to last and it would take some amount of work to completely ruin it. Check out youtube and watch guys take grinders to old pans they’ve found in a skip, clean the rust off and end up with something beautiful.

The seasoning is built up in nice thin layers, it’s bonded to the metal. It absolutely won’t chip, don’t worry. I store my cast iron pans stacked directly inside each other with no issues, I would NEVER do that with my non-stick pans.

If you are worried that having to season your cast iron is a big job or overly complicated. Skip to the end of this blog and I’ll take you through just how easy it actually is.

Myth 2: “You should NEVER wash your cast iron pan with soap.”

The myth: The seasoning on your cast iron is a thin layer of oil and as soap is designed to remove oil, the soap will take the seasoning off.

The truth: OK I understand the misunderstanding here. It is true that you season the pan with a thin layer of oil, but the seasoning itself is actually not oil, it’s a thin layer of polymerised oil.  Let me explain, when you season the pan, you rub on a thin layer of oil and then heat that oil. You do this over and over creating more layers. But when you heat that thin layer of oil it changes its chemical structure and becomes a hard layer which has bonded to the surface of the metal. This is what gives cast iron its non-stick surface, it’s actually no longer an oil, so soap shouldn’t affect it.

However… something you don’t want to do is let it soak in the sink. Obvious iron and water are not best friends, so leave the pan on the cooker until you’ve had dinner if you have to, but don’t leave it sitting in the sink full of water.

Myth 3: “You can’t cook tomatoes and other acidic stuff  in cast iron.”

The myth: Acidic foods react with the metal and give your dinner a weird flavour.

The truth: In a well-seasoned cast iron pan, you have built up that layer of seasoning so the food in the pan should only be coming in contact with the layer of polymerised oil, not any metal. Also cast iron is no different to other cookware like that with a non stick coating. Acidic foods, if left in contact for prolonged periods regularly can damage the coating.

So for this reason, your cast iron pan probably isn’t the choice for making a tomato sauce where you are simmering acidic foods for a long time. On the other hand, a little acid is not going to hurt it. You can fry or roast your tomatoes or even deglaze your pan with red wine. 

A good point to consider though, cast iron cooking can leach trace amounts of iron into your food, this is a good thing as we need iron in our diets.

Myth 4: “You can’t use metal cooking utensils on your cast iron pan, it will scrape the seasoning off!”

The myth: The seasoning in cast iron pans is delicate and will easily chip if you use metal. You should only use wood or silicon utensils.

The truth: You are thinking about non stick coatings. The seasoning in cast iron is actually seriously tough. It’s not just stuck to the surface, it’s actually chemically bonded to the metal. So scrape away with a metal spatula and unless you’re actually gouging at the surface, there shouldn’t be any issues. Any little black bits you see will most likely be burnt food from a previous dinner because you didn’t scrub things with soap after the last meal.

Myth 5: “New cast iron pans are just as good as old grannie’s old cast iron. It’s all cast iron.”

The myth: Cast iron pans are cast iron pans. They are all the same cause well, metal is metal.

The truth: The metal is the same yes, but just like everything else the production methods have changed. In the old days, cast iron pans were made by casting and then polishing the resulting pebbly surfaces until smooth. Vintage cast iron tends to have a satiny, smooth finish. However, like anything, popularity for a product meant production scaled up and was streamlined, this final polishing step was dropped from the process. This means newer cast iron still has that bumpy surface.

It is only a minor thing though. So long as you’ve seasoned your pan properly, both vintage and new cast iron should take on a nice smooth, shiny surface, but modern cast iron will never be quite as non-stick as the vintage stuff. I am so jealous of anyone who has family hand me down cast iron.

Seasoning your cast iron

It is actually really easy to season your cast iron, it’s not a big faff at all but I do have one tip to prevent divorce, so read on.

Try cooking on a bare, unseasoned cast iron pan and not only will you see it rust quickly but food will stick like nobody’s business. So to prevent all of this, we season our pans.

Now I don’t mean salt and pepper, instead, I mean a hard, protective coating that’s created by heating multiple thin layers of oil on the cast iron. As the oil is heated, it bonds to the metal and to itself in a process called polymerisation, as the oil converts into a form of plastic. After enough layers of seasoning have been applied, what you end up with is a hard, blackened skin that protects the metal.

OK admit it, who thoughtI was talking about flavouring?

When you buy a new pan, it might already come “pre-seasoned”, this means it’s already got layer or two of seasoning on there, so the job has been started but I would still recommend giving the pan a good clean to get rid of any manufacturing yuk and giving it a couple of coats of seasoning just to get it perfect.

So how do I season my cast iron?

Step 1: Wash and dry it

Give your pan a good scrub with warm, soapy water and a scrubby sponge, then dry it thoroughly. Even if you are super careful and use your favourite towel, there might still be some water there so shove it on the cooker for a few minutes to just drive off any water.

Step 2: Rub oil all over it and then buff the oil off ( to make sure it’s a thin layer).

Now it’s is clean and dry, rub it all over, all over, inside and out AND the handle with oil. Any oil will do but be aware that different oils have different smoking temperatures. I use plain old vegetable oil.

It’s important that you rub / buff off the oil after as even a little excess can pool and cause sticky bumps and lumps. You want to build up thin, thin, thin layers.

Top tip, use an old rag, tea towel, t shirt etc, something lint free. DO NOT use paper.

Step 3: Heat

Now you have the pan oiled, you need heat to polymerise it. The best way to do this is to put the pan in a hot oven – upside down – for an hour. HOWEVER… things will get smokey, so to prevent divorce (Kate hates when I get the kitchen stinky and smokey), my top tip is to do this in the garden in the BBQ.

The reason we use an oven (or the BBQ) is because we want a nice even heat. This is much better at setting the oil all over the pan.

I put the pans in upside down, it’s just added insurance against any excess oil that decides to run and pool, since gravity will pull it out of the pan.

Step 4: Repeat 3 to 4 Times

When the hour is up, take the pan out. It’s bloody hot though so be VERY careful and rub it once more all over with the oil, buffing it out as before. Repeat this 3 or 4 more times.Once you’re done, just let the pan cool down. You are now ready to go!

Just to allay any fears, you don’t need to do this every time you use your pan. Every time you cook in it with some type of fat, think frying steak, bacon etc, you’ll be laying down more seasoning. So you only need to reseason once in a while to keep on top of things.

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